1. Technical Field
This invention generally relates to bats, such as baseball and softball bats, and more specifically relates to a method of tuning such bats for optimum performance and to bats that are tuned.
2. Background Art
Bats, such as baseball and softball bats, are well known. Many bat manufacturers have attempted to produce more lively bats (bats that would allow players to hit the ball with greater velocity). Such attempts have included the use of composite materials in the structure of tubular bats. Manufacturers thought that the composites would make the bats stiffer and thereby improve their performance. However, stiffer composite bats have generally been less lively than bats produced from more conventional materials, such as aluminum.
Others have attempted to manufacture more lively bats by altering the dimensions of bats made from aluminum, titanium, and composite or combinations thereof. These alterations have generally been done by trial and error, wherein a manufacturer alters the bat dimensions, manufactures a bat, tests the bat's performance to determine whether it is lively, and begins the process again until a more lively bat is produced. These trial-and-error alterations are expensive and time consuming, and moreover, they are not guaranteed to produce advantageous results. However, such alterations have produced some success. For example, it has been found that titanium and aluminum bats having thin-walled barrels generally perform better than such bats having thick-walled barrels. Even this advance has been limited because bats having thin-walled barrels are generally less durable than bats having thick-walled barrels. Therefore, bat manufacturers have been caught in the difficult position of choosing between greater performance and greater durability.
Another example of an attempt at trial-and-error alterations is U.S. Pat. No. 5,624,115 to Baum, issued Apr. 29, 1997 (the '115 patent). The '115 patent discloses a composite bat having a central cavity within the barrel. The '115 patent also discloses that the nature of the composite layers that form the barrel may be adjusted so that, upon impact the barrel undergoes localized deformation and hoop deformation. The 115' patent also states that the cavity increases the hoop spring and decreases the local deformation, and that the size and shape of the cavity may be designed to maximize energy transfer to the ball. However, the '115 patent does not disclose how the energy transfer to a batted ball can be optimized in different bats, and, therefore, its disclosure does not obviate the need for trial-and-error alterations.
The governing authorities in some softball leagues and tournaments have increased the difficulty of the manufacturers' position. These authorities have banned bats that are too lively because of injuries to infielders produced by high-velocity batted balls. Accordingly, these authorities require that all bats be tested before players use them in official games, thereby assuring that the bats are not too lively. The required tests yield a bat performance factor (BPF), wherein a higher number corresponds to a bat having a greater ability to produce high velocities in batted balls. Typically, these authorities require that the BPF of a bat be no greater than 1.20. Thus, it is now desirable in many instances to make a bat that is lively, but not too lively. Trial-and-error alterations are even more time-consuming and expensive to manufacturers trying to achieve optimum results without producing a bat that is too lively.